Sumo, grappling, wrestling, judo, BJJ....these are all basically just extensions of what already exists in nature, something animals (not just turtles, I've posted videos of apes doing what looks like judo too) do instinctively when fighting.

When turtles fight apparently they clinch and try to gain leverage over each other in order to flip/throw their opponent. Amazing!

So in a way, humans didn't really invent grappling arts at all, right? It's just a part of animal nature, learning to use gravity and strength and balance to establish dominance over another animal.

But like many things humans get involved in, we've been able to advance and refine things a bit. I'd be surprised to see a turtle using a triangle leg choke, but you never know.

Still, watching other animals grapple is something I find fascinating.